As the stack configuration of fuel cells, the structure disclosed in PTL1 (given below) uses gaskets to seal in between fuel cells, each including an MEA (membrane electrode assembly) sandwiched between two opposed separators. According to the description of PTL1, the gasket is formed to have an approximately triangular cross section and a bottom surface adhering to one surface of each unit cell. The unit cells are stacked, such that the edges of their gaskets are directed in one single direction.
FIG. 1 illustrates an exemplary state in a prior art stack configuration, wherein a fuel cell 1 as a replacement object is withdrawn from a fuel cell stack 2. As shown in FIG. 1, withdrawal of the fuel cell 1 in the prior art stack configuration causes exposure of gaskets 4 adhering to an adjacent fuel cell 3 adjoining to the withdrawn fuel cell 1. Once the sealing members, such as gaskets, are exposed outside, however, dust and other foreign substances may adhere to the sealing members, which may decrease their sealing power and make it difficult to reuse such sealing members. This accordingly leads to the requirement of replacing the exposed gaskets 4. Replacement of only the gaskets 4 is, however, not allowed, but replacement of the fuel cell 3 with the gaskets 4 adhering thereto is needed. In this manner, replacement of the fuel cell 3 further requires replacement of an adjacent fuel cell under the fuel cell 3. Eventually, all the fuel cells located below the fuel cell 1 as the original replacement object are to be replaced in the state of FIG. 1. In other words, the prior art configuration needs replacement of a larger number of fuel cells than the number of fuel cells as the actual replacement object. This significantly increases the cost for repair of the fuel cell stack.